Special service signaling circuits govern the transmission of signals used in private line, two-PBX (Private Branch Exchange) telecommunications systems to perform functions such as supervision (answer and disconnect) and address signaling (dialing) to control the operation of switching machines in the telecommunications system.
The present invention tests special service circuits at a customer demarcation point. Before 1984 there was not a specific need to establish a demarcation point. Due to this absence of need, special service circuits were installed and maintained by their respective companies.
After Jan. 1, 1984 (Bell system divestiture) there existed two classes of providers--(1) the telephone company or carrier interconnect and (2) the premise equipment facility. Precisely because of this (two or more) company arrangement, there had to be a clearly established line of demarcation. At this created demarcation point the companies and their respective circuits were separated and defined as a point of presence.
Soon thereafter, questions concerning installation and maintenance up to this demarcation point began to create responsibility problems. For example, if a customer who owned or leased premise equipment such as PBX experienced special service circuit trouble, there could be a question concerning the trouble responsibility--telephone company or premise equipment provider.
Up until divestiture all special service circuits were installed and maintained from one end to the other. Now it is apparent that the same type of circuit needs to be tested from somewhere in between the near and far end toward both providers.
With all of the foregoing factors in mind, there has arisen an acute need for a simple yet practical test device. Previous to divestiture it was a simple matter to transpose the signal leads of a good circuit with a bad one and utilize a voltmeter to test for voltage and ground. After divestiture however, this method is no longer possible.
Further, there is no longer any method of testing which employs a technique designed to verify signaling leads by exercising or activating the premise equipment. The present invention was designed to utilize this method as well as accomplish simple testing techniques.